fix sqls path

[kawagh]

I tried :LspInstallServer sqls (in Linux NOT Windows) and got below message.

go: downloading github.com/lighttiger2505/sqls v0.2.28
go: github.com/lighttiger2505/sqls@latest: version constraints conflict:
        github.com/lighttiger2505/[email protected]: parsing go.mod:
        module declares its path as: github.com/sqls-server/sqls
                but was required as: github.com/lighttiger2505/sqls

So I modified path and retried installation.

go: downloading github.com/sqls-server/sqls v0.2.28
go: downloading github.com/sourcegraph/jsonrpc2 v0.2.0
...